It’s not all about personality, the famous difficulty between Barack Obama and Benjamin Netanyahu. They are indeed very different people, and by all accounts far from friends. But the Iranian nuclear dilemma would guarantee tension between any American president and Israeli prime minister, if only because the Jewish state brings its own approach to security matters: Less patient, more martial, and more than a bit pugnacious. Israelis born in the country are known as sabras, literally, prickly pears — their own defense is what they bristle with.

Netanyahu, elected twice as their leader, may be the politician most disposed to project – not to say channel – the national character. Famous for his sensitivity to public opinion, he enjoys comfortable approval ratings and an electoral horizon with no notable challenger in sight.

“I thought his stance toward Obama was going to be the end of him,” says a political consultant who has worked with Netanyahu. But “he keeps getting stronger and stronger.”

Analysts say it’s not a question of popularity – few Israelis express great affection for Netanyahu. But he is a master communicator; and in Washington he articulates an Israeli consensus on security that has grown only firmer as the population — especially young Israelis — grows less tolerant of attacks on the state and more inclined to value a “strong leader” above all, as polls show.

“Bibi was elected prime minister,” says Moshe Arens, a former defense minister credited with bringing Netanyahu into the conservative Likud party that has dominated Israel’s last quarter century nearly as thoroughly as liberal Labor dominated its first decades. “What he’s saying is more or less in line with the traditional views held by the Likud Party, which has been in power, more or less, since 1977. It’s nothing personal that he’s been pushing.”

Zalman Shoval, who served twice as Israel’s ambassador to Washington, says Israelis are no longer afraid to confront its one indispensable ally.

“There’s such a lot of talk about different personalities and chemistry, but at the end of the day what’s important is interests, “ Shoval says. When American and Israeli interests coincide, as they did in the 1991 First Gulf War, then-prime minister Yitzhak Shamir, though a fierce hawk, agreed to absorb Scud attacks from Saddam Hussein’s Iraq in order to avoid provoking dissent in the international coalition George H.W. Bush had assembled to drive the dictator out of Kuwait.

“Bush 41 and Shamir whose personal chemistry was lousy, when there was a common interest, the Gulf War, it was a love story,” says Shoval. “Bad chemistry became good physics.”

The wartime romance ended after the 100 hours of fighting, however. Shamir had to dragged to the Madrid peace conference with the Palestinians, finally coerced by Bush’s threat to withhold aid for Russian immigrants who would, once settled in Israel, make the country that much more conservative. But in the next year Shamir lost, partly for alienating the country’s most important ally, Shoval recalls. “In the days of Shamir and Bush 41, the view was, ‘Look, we can’t afford to fight with the Americans,’” he says. ‘Now the feeling is ‘It’s good to have a prime minister who stands up to the Americans.’ I think there’s more self-assurance. Israelis are pretty sure of themselves.”

The problem, in the case of Iran’s nuclear program, is that the lack of rapport between Obama and Netanyahu threatens to prevent the leap of faith required for a common front. With Iran now moving key nuclear equipment into underground bunkers beyond the reach of Israel’s air force, the window for an Israeli airstrike is closing. Obama says the United States, which has the military flexibility to act later, would use it to prevent Iran building atomic weapons, but first wants to give time to new international sanctions that even Israeli leaders describe as “crippling.”

So it’s a question of trust, something the two leaders have not yet seen in one another, notes Amos Yadlin, the retired major general who until 15 months ago ran Israel’s military intelligence apparatus. He summarized the issue in a New York Times op-ed in advance of Monday’s White House meeting between the leaders.

“I think it has to do with three years they have spent together trying to navigate the main issues of the two countries,” Yadlin tells TIME, describing the misgivings between Obama and Netanyahu. “I think on both sides there will be people with injuries, with some memories from the past that make this trust more difficult to achieve.”

And beyond the personal misgiving stands a national one.

“Israel’s not willing to subcontract its defense,” Yadlin says. “We have never asked the Americans to fight for us.”

“Look,” says Shoval, “I think most Israelis still have a sort of subconscious trauma about the Holocaust, even if you know the younger generation was not directly concerned. I think that Israelis feel that they can only at the end of the road rely on themselves for security.”

“It’s not a question of appetite,” says Arens. “It’s a matter of: We are responsible for our existence.”

Karl Vick has been TIME's Jerusalem bureau chief since 2010, covering Israel,the Palestine territories and nearby sovereignties. He worked 16 years at the Washington Post in Nairobi, Istanbul, Baghdad, Los Angeles and Rockville, MD.